1. Field of the Invention
This invention relates to exercise equipment, and in particular to low impact exercise equipment of a type designed to simulate climbing or jogging while eliminating shock impacts to the user's joints.
2. Description of the Prior Art
Exercise equipment designed to simulate climbing or jogging has long been known. U.S. Pat. No. 2,079,594 discloses motor powered equipment which reciprocates a user's legs upwardly and downwardly as the user rides upon it. Equipment having relatively complex hydraulics for phasing the movement of steps upon which users climb are shown in U.S. Pats. Nos. 4,681,316, 3,529,474 and 3,758,112. A hand and foot exercising device wherein pedals and grips are interconnected by means of a chain and sprocket arrangement is shown in U.S. Pat. No. 3,381,958.
Equipment upon which a user balances while stepping his feet upwardly and downwardly is shown in both U.S. Pats. Nos. 3,511,500 and 3,747,924. In the latter patent, pulleys mounted below the platforms on which a user stands are employed to cause one pedal to move upwardly while another is pressed downwardly by the user. A four-bar linkage is employed to maintain the foot pedals in a horizontal position.
A spring resistance jogging device is shown in U.S. Pat. No. 3,628,791. In this equipment pedals are depressed alternatively as the user jogs in place. The pedals are returned to their horizontal position by a spring positioned therebeneath as the user transfers his weight from one foot to the other.
A training platform including pivoting foot supports interconnected by ropes to a pivoting arm support is disclosed in U.S. Pat. No. 3,792,860. This patent does not disclose the use of any resistance means to control the movement of the foot pedals which consequently pivot unchecked to crash onto the supporting base as the user shifts his weight from one foot pedal to the other. U.S. Pat. No. 4,600,187 discloses a device for simulating walking up steps wherein the treads are mounted on arms interconnected by a rocker plate which causes one step to move upwardly as the other is moved downwardly. Brake shoes are provided to resist rotation of the rocker plate and consequent movement of the foot pedals.
A device for simulating ice skating is shown in U.S. Pat. No. 3,756,595. In this equipment shock absorbers are provided to resist the rearward movement of the user's feet. The foot supports are not interconnected so that the backward movement of one foot pedal does not cause the other to move forward for the next stroke. An exercise stair device is disclosed in U.S. Pat. No. 3,970,302 which includes a pair of foot pedals interconnected by a rope extending over a pulley so that when one pedal moves down the other moves up and vice versa. The support frame for the equipment includes four vertical supports mounted on a base. Shock absorbers are mounted below the foot pedals and extend thereabove to provide a counterforce to the pivotal movement imparted to the foot pedals by the user.
Recent U.S. Pat. No. 4,659,075 discloses a wide variety of exercise devices, including a climbing device shown in FIGS. 17-19, mounted on a pair of A-shaped frames wherein the steps are interconnected by a cord and pulley arrangement for reciprocal motion. A friction brake is associated with the pulley to control the resistance to movement of the foot pedals along the frame legs. Other variations are shown in FIGS. 20-24, including mounting the steps on the ends of hydraulic cylinders. No indication is given as to how the pistons would be retracted into the hydraulic cylinders after the user depresses the step connected thereto.
Known exercise equipment is either unduly complex in structure or operation or fails to provide a low impact means for exercising all major lower body muscle groups.